Abstract An electrostatic spray gun in which coating or other material is metered through an orifice adjustable in size to accommodate materials of various viscosities and consistencies and is thereafter atomized upon being injected as a conical fluid sheet into a central stream of high velocity air. Adjustment of the orifice and thus of the flow rate of the material is accomplished by rotating the spray head relative to the gun body. Further atomization of the material and development of the spray are produced by fluid streams exiting through an annular opening and other fluid orifices spaced around the spray outlet opening. The atomized particles are charged electrically by a rearwardly directed corona discharge established between a corona electrode supported on the spray head and an attractor ring positioned on the spray head in surrounding relation to the spray outlet opening.
Apparatus according to claim 1, in which the opening in the front surface of the valve and the spray outlet opening in the nozzle member are circular and coaxially, the diameter of the opening in the valve being smaller that the diameter of the outlet opening to allow free flow of the spray material from the first annular chamber into the atomizing fluid stream.
Claim 2
Dependent Claim
59 words
Apparatus according to claim 2 in which a plurality of forwardly and inwardly directed orifices are provided in the ring, the orifices being spaced circumferentially around the annular opening surrounding the spray outlet opening and communicating with the second annular chamber to discharge a plurality of atomizing fluid streams against the spray to further atomize and develop the spray.
Claim 3
Dependent Claim
34 words
Apparatus according to claim 3, further comprising mEans for establishing a corona discharge in opposition to the spray flow between a corona electrode disposed forwardly of the spray outlet opening and the spray head.
Claim 4
Dependent Claim
83 words
Apparatus according to claim 4 in which the corona electrode is supported on the spray head and extends transversely into spray and thereafter curves rearwardly to terminate at a point in front of the spray outlet opening, and in which the portion of the ring adjacent the spray outlet opening is recessed from the foremost surface of the ring so that the corona discharge is established principally between the corona electrode and the portions of the nozzle member surrounding the spray outlet opening.